What Is Stevens-Johnson Syndrome (Ocular)?

Mechanism: The Immune System "Overdrive"

SJS is considered a delayed hypersensitivity reaction. The body's immune system overreacts to a trigger, usually a drug like sulfonamides, anticonvulsants, or certain NSAIDs. This reaction leads to the death of epithelial cells (the top layer of skin and mucous membranes). In the eye, this means the protective surface of the cornea and the moisture-producing cells of the conjunctiva are destroyed. When the "skin" of the eye dies and sheds, it leaves behind raw, bleeding surfaces that are prone to scarring.

Chronic Complications: Symblepharon and Ankyloblepharon

The healing process in SJS can be just as damaging as the initial reaction. As the raw surfaces of the inner eyelid and the eyeball try to heal, they may stick to one another.

Symblepharon - This occurs when the inner lining of the eyelid scars and attaches directly to the eyeball.

Ankyloblepharon - This is a more severe form where the edges of the upper and lower eyelids fuse together. These adhesions restrict eye movement and can eventually lead to the eyelids turning inward (entropion), causing the eyelashes to rub against and scar the cornea (trichiasis).

The Loss of "Stem Cells"

The most devastating long-term ocular effect of SJS is Limbal Stem Cell Deficiency (LSCD). The limbus is a ring around the cornea that produces new clear cells. SJS often destroys these stem cells. Without them, the cornea cannot repair itself, and the opaque, blood-vessel-rich skin of the white of the eye (conjunctiva) begins to grow over the clear window of the eye. This process, known as conjunctivalization, leads to permanent blindness unless a stem cell transplant is performed.

Management: Amniotic Membrane Grafting

During the acute hospital phase, ophthalmologists often use Amniotic Membrane Grafting (AMG). A thin piece of tissue from a donor placenta is placed over the eye or tucked into the eyelids. This tissue acts as a biological "bandage" that reduces inflammation, prevents the surfaces from sticking together, and provides a scaffold for the patient's own cells to regrow. This intervention is the most effective way to prevent the blinding scarring associated with the disease.